Here is what I believe is a complete (no cherry-picking) list of analyses taking advantage of random-assignment experiments of the effect of vouchers on participants. As I’ve previously written, 9 of the 10 analyses show significant, positive effects for at least some subgroups of students.

All of them have been published in peer reviewed journals or were subject to outside peer review by the federal government.

Four of the 10 studies are independent replications of earlier analyses. Cowen replicates Greene, 2001. Rouse replicates Greene, Peterson, and Du. Barnard, et al replicate Peterson and Howell. And Krueger and Zhu also replicate Peterson and Howell. All of these independent replications (except for Krueger and Zhu) confirm the basic findings of the original analyses by also finding positive effects.

Anyone interested in a more complete discussion of these 10 analyses and why it is important to focus on the random-assignment studies, should read Patrick Wolf’s article in the BYU Law Review that has been reproduced here.